Process for the manufacture of sodium bisulfate in a directly-calcinable form.



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PETER Lfil-TFLTEE, 0F VIENNA, AUSTRIA-HUNGARY.

PROCESS FOR THE MANUFACTURE OF SODIUM BISULCFATE- IN A DIREG'ELY- I GALGINABLE FGRM.

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Be it known that I, PETER Lorrnnn, manager, a subject of the Emperor of Germany, and a resident oi Vienna, in the Empire of .-'\ushin-Hungary, (whose postbiiice address is Vienna, l. Kolowratring 6,) have invented Improvements in the Process for the Mannfacture of {indium Bisulfate in a Directly- Calcinable Form, of which the following is a specification. Many attempts have already been made to produce the neutral sulfate from sodium bisulfate without the-necessity of producing at the same time hydrochloric acid. According to one known process, the bisulfate is heated with carbon, whereby neutral sulfate is formed by the action of the heat, (see German patent specification No. 63189). It has also been proposed to replace a part of the carbon powder by sawdust with the intention of preventing: an agglomeration of the mass, in the calcination process, (see British patent specification No. 6898 of A. l). 1904). It has, however, been attempted in vain to decompose the iii-sulfate by a process suitable for operations on a large scale, by means of heat alone Without any additions. The reason for this is that bi-sulfate melts in the calcination process, and no apparatus is ableto withstand permanently the act-ion of molten bi-sul'fate owing); to the veryhigh calcination temperature e .ployed in the known process. 'Ithas been attempted to prevent the melting of the sodium bi'sulfate by subjecting it to the calcining operation in admixture with silica or silicates'or any substance, thatis not acted upon by bissul fate, for instance the anhydrous sulfates of sodium, potassium, calcium. or the like (see,

Austrian patent specification No. @9478). These attempts, however, have also led to no process suitable for c'ominercial working, in consequence of the high calcination temperature andthe incompletely obviated melting of the sodium bisultate. Now the improved process forming the subject of the present invention allows of producing sodium bi-sulfate in av form in which it can be calcined directly without additional substances without melting.

One form of the improved process consists inpassing a asifiable substance. pref erably a carbonizable substance directly into the hot liquid sodium bisultate drawn-from Specification of Letters Yatent.

the nitric acid retort and allowing this mixture to cool and set. This produces a violent evolution of gas and the liquid bisultate sets with generation of gas to a loose spongy mass, which is characterized by a low spe-' cific gravity and great porosity. The production of the bi-sulfate in a porous form would seem to be due to the generation of yapor or gas caused by the introduction of vapor forming, or gas-generating substances. The use of carbonizable substances, such' as cellulose-containing materials, forinstance sawdust, peat and the likeyas gas generators, has the great advantage that carbon is incorporatedwith the bisulfate during the setting, which carbon acts as a reducing agentin the calcination of the bi Patented July 28, 1914. Application filed. December 19, 1913. Serial No. 805,744; I

sulfate in the mufiie, and is driven out in the ITOIDlTlil carbonic acid. Consequently the porosity of the bisulfate increases during thecalcination and. therefore its melting tendency is still further diminished and moreover the calcination temperature is reduced by the action of the reducing agent, so that the calcination can be effected at-the temperature norn." .ly existing in the sulfate Inu'lile furnace.

The improved process is preferably carried into effect by stirring the hot sulfate which isdrawn off into any suitable stirring apparatus in the nitric acid factory together with about 2 to 10% of sawdust or the like, and then allowing the mixture to cool in a cooling tank. Experiments have shown that the percentage of acid contained in the bisultate is only inappreciably affected here by. In the aforesaid cooling tank the bisultate forms in the shape of a blue 1 spongy mass which turns white when calcined without melting, and which produces s neutral. sulfate of normal composition.

Having now particularly described and ascertained the nature of my said invention and in what manner-the same is to be performed, I declare that what I claim is v 1 A process for producing sodium bisul'tate in a directly calcinable form, which consists in mixing gasifiable substances of an organic nature with the hot liquid bi-sulfate, and then allowing the mixture to set,

whereby porosity of the mass is produced by the gasification during setting so that the fate in a directly calcinable form, which con I Without melting and will produce a neutral sists in mixing cellulose-containing materials sulfate of normal composition. with the hot liquid bisulfate, and then allowi In witness whereof,- I have hereunto signed ing the mixture to set, whereby porosity of my name in the presence of two subscribing glee mass is prodlgzed the gasificatiordi Witnesses. v urin setting so t at t e mass-is 'rendere more easily celcinable. PETER LOFFLER' I 3. As a new product of manufacture so Witnesses: clium bi-sulfate in the form of a black spongy HUGO KEIK, '10 mass, which will-burn White when calcined Am MARIA BERGER. 

